Fan system and temperature-sensing protecting device thereof

ABSTRACT

A fan system includes a fan module, a starting module, a temperature-sensing element and a controlling module. The starting module is electrically connected with the fan module for starting it. The temperature-sensing element generates a sensing signal in accordance with an ambient temperature. The controlling module receives the sensing signal for controlling the starting module. When the ambient temperature is higher than a first temperature or is lower than a second temperature, the controlling module controls the starting module to disable the fan module.

CROSS REFERENCE TO RELATED APPLICATIONS

This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 094141110 filed in Taiwan, Republic of China on Nov. 23, 2005, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a fan system and a temperature-sensing protecting device thereof and, in particular, to a fan module with a temperature-sensing element and a temperature-sensing protecting device thereof.

2. Related Art

In general, most electronic systems have a fan system to ensure that the electronic systems can be kept at the normal working temperature such that the electronic system can operate normally. The fan system has predetermined operating specifications, such as the operating temperature and the likes.

As shown in FIG. 1, a conventional fan system 1 mainly includes a fan module 11 and a starting module 12. The starting module 12 is used for enabling the fan module 11 so as to dissipating heat. However, when the operating temperature of the fan system 1 is too high or too low, the damage of the fan system 1 may occur. To solve this problem, the prior art usually adopts an analog starting control chip 13 to sense the operating temperature of the fan system 1. If the sensed operating temperature is too high or too low, the fan system 1 will be automatically disabled for the protection purpose.

However, the analog starting control chip 13 has a high price, so that the overall manufacturing cost of the fan system 1 is too high. Besides, the analog starting control chip 13 cannot provide the function of soft-start.

Therefore, it is an important subject of the invention to provide a fan system and a temperature-sensing protecting device thereof to solve the above mentioned problem.

SUMMARY OF THE INVENTION

In view of the foregoing, the invention is to provide a fan system, which disables the fan system when the operating temperature detected by a temperature-sensing element is too high or too low, and a temperature-sensing protecting device thereof.

To achieve the above, a fan system of the invention includes a fan module, a starting module, a temperature-sensing element and a controlling module. In the invention, the starting module is electrically connected with the fan module for starting it. The temperature-sensing element generates a sensing signal in accordance with an ambient temperature. The controlling module receives the sensing signal for controlling the starting module. When the ambient temperature is higher than a first temperature or is lower than a second temperature, the controlling module controls the starting module to disable the fan module.

To achieve the above, the invention also discloses a temperature-sensing protecting device, which cooperates with a fan module. The temperature-sensing protecting device includes a starting module, a temperature-sensing element and a controlling module. The starting module is electrically connected with the fan module for starting it. The temperature-sensing element generates a sensing signal in accordance with an ambient temperature. The controlling module receives the sensing signal for controlling the starting module. When the ambient temperature is higher than a first temperature or is lower than a second temperature, the controlling module controls the starting module to disable the fan module.

As mentioned above, the fan system and temperature-sensing protecting device of the invention have a temperature-sensing element for sensing the operating temperature of a fan system. Then, when the operating temperature is too high or too low, the fan module is disabled for protecting it. Compared with the prior art, the fan system and temperature-sensing protecting device of the invention utilize the temperature-sensing element to detect the operating temperature for ensuring that the fan system can operate normally and replacing the analog starting control chip to reduce the overall manufacturing cost.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein:

FIG. 1 is a schematic diagram of a conventional fan system;

FIG. 2 is a schematic diagram of a fan system according to a preferred embodiment of the invention; and

FIG. 3 is a circuit diagram of a fan system according to a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.

FIG. 2 is a schematic illustration showing a fan system according to a preferred embodiment of the invention. The fan system 2 may be installed inside an electronic system (not shown) in order to dissipate heat.

The fan system 2 includes a fan module 21, a starting module 22, a controlling module 23 and a temperature-sensing element 24. The fan module 21 has a fan. Of course, the fan module 21 may have a plurality of fans according to the heat dissipating requirement so as to enhance the heat dissipating effect.

In the fan system 2, the starting module 22 is electrically connected with the fan module 21 so as to start it. The temperature-sensing element 24 produces a sensing signal V_(t) in accordance with an ambient temperature. The temperature-sensing element 24 may be a thermistor (thermal resistor). In this embodiment, the temperature-sensing element 24 is a negative temperature coefficient (NTC) thermistor. The ambient temperature may be the internal temperature of the electronic system, so that the temperature-sensing element 24 produces the sensing signal V_(t), e.g. a voltage value, in accordance with an ambient temperature. Based on the characteristic of the NTC thermistor, the resistance of the temperature-sensing element 24 decreases and the voltage of the sensing signal V_(t) decreases when the internal temperature of the electronic system increases. On the contrary, the resistance of the temperature-sensing element 24 increases and the voltage of the sensing signal V_(t) increases when the internal temperature of the electronic system decreases.

The controlling module 23 receives and controls the starting module 22 in accordance with the sensing signal V_(t). When the ambient temperature is higher than a first temperature or lower than a second temperature, the controlling module 23 controls the starting module 22 to disable the fan module 21 for preventing the fan system 21 from being damaged caused by the improper operation under abnormal operating temperature. In this embodiment, the first temperature and the second temperature are determined in accordance with the operating specifications of the fan system 2. The first temperature is the upper limit operating temperature of the fan system 2 such as 70° C., and the second temperature is the lower limit operating temperature of the fan system 2 such as −40° C.

With reference to FIG. 3, the controlling module 23 includes a first control unit 231 and a second control unit 232. In this embodiment, the first control unit 231 comprises a first switch element Q₁ and a first comparator element U₁. The second control unit 232 comprises a second switch element Q₂ and a second comparator element U₂.

Each of the first switch element Q₁ and the second switch element Q₂ may be a transistor or any other electronic element with the switch function. In this embodiment, the first the first switch element Q₁ and the second switch element Q₂ are both NMOS transistors.

Regarding to the first control unit 231, a drain D of the first switch element Q₁ is electrically connected with the starting module 22 for controlling the starting module 22, and a source S of the first switch element Q₁ is grounded.

The first comparator element U₁ includes a first input terminal input₁ a second input terminal input₂, and an output terminal output. In this embodiment, the first input terminal input₁ is a noninverting input terminal and the second input terminal input₂ is an inverting input terminal.

The first input terminal input₁ receives a first reference signal V_(ref1), which is produced from a voltage-dividing circuit composed of at least two resistors. The specifications of the resistors can be chosen according to the requirement of user for adjusting the first reference signal V_(ref1). In this case, the first reference signal V_(ref1) is used to determine the upper limit operating temperature of the fan system 2. The second input terminal input₂ receives the sensing signal V_(t). The output terminal output is electrically connected with a gate G of the first switch element Q₁ for controlling the first switch element Q₁. To make the invention more comprehensive, the following description assumes that the voltage gain value of the first comparator element U₁ is equal to 1. When the sensing signal V_(t) is lower than the first reference signal V_(ref1), the output terminal output delivers a positive voltage to start the first switch element Q₁ so as to control the starting module 22 to disable the fan module 21.

In addition, the second input terminal inputs and the output terminal output of the first comparator element U₁ are electrically connected with a resistor R₁, so that the first comparator element U₁ may have a precise temperature transition characteristic. For example, the first control unit 231 is supposed to control the starting module 22 to disable the fan module 21 when the first temperature reaches 70° C. However, the starting module 22 practically disables the fan module 21 when the first temperature is 72° C. due to the characteristic of the electronic element, which causes an error originally. For preventing the above mentioned problem, the resistor R₁ is set between the second input terminal input₂ and the output terminal output of the first comparator element U₁ for compensating the feedback voltage value. Therefore, the first comparator element U₁ can precisely control the starting module 22 to disable the fan module 21 when the temperature reaches 70° C. Accordingly, the precise temperature transition characteristic can be achieved.

Regarding to the second control unit 232, a drain D of the second switch element Q₂ is electrically connected with the starting module 22 for controlling it, and a source S of the second switch element Q₂ is grounded

The second comparator element U₂ includes a first input terminal input₁, a second input terminal input₂, and an output terminal output. In this embodiment, the first input terminal input₁ is a noninverting input terminal, and the second input terminal input₂ is an inverting input terminal.

The first input terminal input₁ receives the sensing signal V_(t) and the second input terminal input₂ receives a second reference signal V_(ref2) producing from the voltage-dividing circuit composed of at least two resists. The specifications of resistors can be chosen according to the requirement of user for adjusting the second reference signal V_(ref2). In this case, the second reference signal V_(ref2) is used to determine the lower limit operating temperature of the fan system 2. The output terminal output is electrically connected with a gate G of the second switch element Q₂ for controlling the second switch element Q₂. To make the invention more comprehensive, the following description assumes that the voltage gain value of the second comparator element U₂ is equal to 1. When the sensing signal V_(t) is higher than the second reference signal V_(ref2), the output terminal output delivers a positive voltage to start the second switch element Q₂ so as to control the starting module 22 to disable the fan module 21. In addition, a resistor R₂ is set between input terminal input₁ and the output terminal output of the second comparator element U₂, and the operation of the resistor R₂ is the same as that of the above-mentioned resistor R₁. Therefore, the second comparator element U₂ may have precise temperature transition characteristic.

As mentioned above, when the sensing signal V_(t) is lower than the first reference signal V_(ref1), or higher than the second reference signal V_(ref2), both the output terminals output of the first comparator element U₁ and the second comparator element U₂ deliver a positive voltage signal in order to control the starting module 22 to disable the fan module 21.

In this embodiment, the starting module 22 includes a third switch element Q₃, a fourth switch element Q₄, at least a capacitor C, at least a resistor R₃, and a plurality of diodes D₁ and D₂. Each of the third switch element Q₃ and the fourth switch element Q₄ is a transistor or any other electronic element with the switch function. In this embodiment, the third switch element Q₃ is a PMOS transistor, and the fourth switch element Q₄ is an NMOS transistor.

A source S of the third switch element Q₃ is electrically connected with the diodes D₁ and D₂. A drain D of the third switch element Q₃ is electrically connected with the fan system 21 for starting the fan system 21. A gate G of the third switch element Q₃ is electrically connected with a drain D of the fourth switch element Q₄. A terminal of the capacitor C is electrically connected with the source S of the third switch element Q₃. The resistor R₃ is electrically connected with another terminal of the capacitor C. In addition, each of the diodes D₁ and D₂ may be a Schottky diode for avoiding the reverse current. A gate G of the fourth switch element Q₄ is electrically connected with the drain D of the first switch element Q₁ and the drain D of the second switch element Q₂.

The operation principle of the fan system 2 will be described in the following. When the internal temperature of the electronic system is between the first temperature and the second temperature (the temperature range of normal operation), the sensing signal V_(t) of the temperature-sensing element 24 is higher than the first reference signal V_(ref1) and lower than the second reference signal V_(ref2). In this case, the first switch element Q₁ and the second switch element Q₂ will be turned off and the fourth switch element Q₄ will be turned on.

Then, the capacitor C starts to charge. When the voltage value of the capacitor C reaches the starting voltage of the third switch element Q₃, the third switch element Q₃ is turned on to enable the fan module 21 for dissipating the heat. To be noted, the charge circuit of the capacitor C and the resistor R₃ enables the current flowing through the fan module 21 to increase at a slow rate such that the effect of soft starting can be achieved.

When the internal temperature of the electronic system is higher than the first temperature, the sensing signal V_(t) is lower than the first reference signal V_(ref1) to turn on the first switch element Q₁. Accordingly, the fourth switch element Q₄ and the third switch element Q₃ are turned off to disable the fan module 21 in order to achieve the protection and efficiency.

Similarly, when the internal temperature of the electronic system is lower than the second temperature, the sensing signal V_(t) is higher than the second reference signal V_(ref2) to turn on the second switch element Q₂. Accordingly, the fourth switch element Q₄ and the third switch element Q₃ will be turned off to disable the fan module 21 in order to achieve the protection and efficiency. As mentioned above, the temperature-sensing element 24 of the fan system 2 senses that whether the internal temperature is higher than the upper limit operating temperature or lower than the lower limit operating temperature. If so, the fan system 2 will compulsorily disable the fan module 21 for preventing it from damage.

The invention also discloses a temperature-sensing protecting device, which cooperates with a fan module. The temperature-sensing protecting device includes a starting module, a temperature-sensing element and a controlling module. In this embodiment, the starting module, temperature-sensing element and controlling module of the temperature-sensing protecting device have the same constructions and functions as those of the previously mentioned starting module 22, temperature-sensing element 24 and controlling module 23, so the detailed descriptions thereof will be omitted for concise purpose.

As mentioned above, the fan system and temperature-sensing protecting device of the invention have a temperature-sensing element for sensing the operating temperature of a fan system. Then, when the operating temperature is too high or too low, the fan module is disabled for protecting it. Compared with the prior art, the fan system and temperature-sensing protecting device of the invention utilize the temperature-sensing element to detect the operating temperature for ensuring that the fan system can operate normally and replacing the analog starting control chip to reduce the overall manufacturing cost.

Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention. 

1. A fan system comprising: a fan module; a starting module electrically connected with the fan module for starting the fan module; a temperature-sensing element for generating a sensing signal in accordance with an ambient temperature; and a controlling module receiving the sensing signal for controlling the starting module, wherein the controlling module controls the starting module to disable the fan module when the ambient temperature is higher than a first temperature or lower than a second temperature.
 2. The fan system of claim 1, wherein the controlling module comprises: a first controlling unit electrically connected with the temperature-sensing element and controlling the starting module in accordance with the sensing signal, wherein the first controlling unit controls the starting module to disable the fan module when the ambient temperature is higher than the first temperature; and a second controlling unit electrically connected with the temperature-sensing element and controlling the starting module in accordance with the sensing signal, wherein the second controlling unit controls the starting module to disable the fan module when the ambient temperature is lower than the second temperature.
 3. The fan system of claim 2, wherein the first controlling unit comprises: a first switch element electrically connected with the starting module; and a first comparator having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal receives a first reference signal, the second input terminal receives the sensing signal, and the output terminal is electrically connected with the first switch element for controlling the first switch element.
 4. The fan system of claim 3, wherein the second controlling unit comprises: a second switch element electrically connected with the starting module; and a second comparator having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal receives the sensing signal, the second input terminal receives a second reference signal, and the output terminal is electrically connected with the second switch element for controlling the second switch element.
 5. The fan system of claim 4, wherein the first switch element and the second switch element are transistors, respectively.
 6. The fan system of claim 1, wherein the starting module comprises: a third switch element having a terminal electrically connected with the fan system for controlling the fan system; a fourth switch element electrically connected with the third switch element for controlling the third switch element; a capacitor having a terminal electrically connected with the third switch element; a resistor electrically connected with the capacitor; and at least a diode having a first terminal for receiving an input voltage and a second terminal electrically connected with the third switch element.
 7. The fan system of claim 6, wherein the third switch element and the fourth switch element are transistors or any other electronic elements with the switch function, respectively.
 8. The fan system of claim 1, wherein the temperature-sensing element is a thermistor or a negative temperature coefficient (NTC) thermistor.
 9. A temperature-sensing protecting device, which cooperates with a fan module, comprising: a starting module electrically connected with the fan module for starting the fan module; a temperature-sensing element for generating a sensing signal in accordance with an ambient temperature; and a controlling module receiving the sensing signal for controlling the starting module, wherein the controlling module controls the starting module to disable the fan module when the ambient temperature is higher than a first temperature or lower than a second temperature.
 10. The temperature-sensing protecting device of claim 9, wherein the controlling module comprises: a first controlling unit electrically connected with the temperature-sensing element and controlling the starting module in accordance with the sensing signal, wherein the first controlling unit controls the starting module to disable the fan module when the ambient temperature is higher than the first temperature; and a second controlling unit electrically connected with the temperature-sensing element and controlling the starting module in accordance with the sensing signal, wherein the second controlling unit controls the starting module to disable the fan module when the ambient temperature is lower than the second temperature.
 11. The temperature-sensing protecting device of claim 10, wherein the first control unit comprises: a first switch element electrically connected with the starting module; and a first comparator having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal receives the first reference signal, and the second input terminal receives the sensing signal, and the output terminal is electrically connected with the first switch element for controlling the first switch element.
 12. The temperature-sensing protecting device of claim 11, wherein the second control unit comprises: a second switch element electrically connected with the starting module; and a second comparator having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal receives the sensing signal, the second input terminal receives a second reference signal, and the output terminal is electrically connected with the second switch element for controlling the second switch element.
 13. The temperature-sensing protecting device of claim 12, wherein the first switch element and the second switch element are transistors or any other electronic elements with the switch function, respectively.
 14. The temperature-sensing protecting device of claim 12, wherein the first input terminal of the first comparator or the second comparator is a noninverting input terminal, and the second input terminal of the first comparator or the second comparator is an inverting input terminal.
 15. The temperature-sensing protecting device of claim 11, wherein the second input terminal and the output terminal of the first comparator are electrically connected with a resistor, respectively.
 16. The temperature-sensing protecting device of claim 12, wherein the first input terminal and the output terminal of the second comparator are electrically connected with a resistor, respectively.
 17. The temperature-sensing protecting device of claim 9, wherein the starting module comprises: a third switch element having a terminal is electrically connected with the fan system for controlling the fan system; a fourth switch element electrically connected with the third switch element for controlling the third switch element; a capacitor having a terminal electrically connected with the third switch element; a resistor electrically connected with the capacitor; and at least a diode having a first terminal for receiving an input voltage and a second terminal electrically connected with the third switch element.
 18. The temperature-sensing protecting device of claim 17, wherein the third switch element and the fourth switch element are transistors or any other electronic elements with the switch function, respectively.
 19. The temperature-sensing protecting device of claim 9, wherein the temperature-sensing element is a thermistor or a negative temperature coefficient (NTC) thermistor. 